Age is the most important number that teams look at when they want to add a player to their team. In basketball, the span of a player's his "prime" is usually considered to be between 25 and 32. A player normally reaches his peak at the age of 27 or 28 because that's usually the time when athleticism and basketball intelligence reach the highest point.
But how do players perform after they age past their so-called prime? Some people like Kobe Bryant and Paul Pierce have sustained their level of production throughout the years, while former All-Star players like Vince Carter and Jerry Stackhouse have become mere role players on their respective teams.
Marion isn't the explosive athlete he once was, but he is still a major contributor to a struggling Dallas team. His averages of 10.0 ppg, 8.2 rpg and 2.7 apg won't blow anyone away, but on every team he has been on, Marion has always done the dirty work.
He is the Mavericks' best defender, and best rebounder, which is saying a lot considering he's playing with two capable rebounders in Chris Kaman and Elton Brand. Marion is in every one of the Mavericks' top 20 lineups that they've used this season.
Ginobili seems to have been starting to decline the past two seasons, but make no mistake, he is still an elite player and a top-five shooting guard in the league. His minutes and some nagging injuries may be the reason why his production has gone down, since he has only been getting 23.8 mpg compared to the 30.3 mpg in the 2010-2011 season.
Ginobili may be the third-best player on the San Antonio Spurs, but he is leading the team in plus-minus rating at plus-10.3, ahead of both Tim Duncan and Tony Parker. When healthy, Ginobili can still light up the scoreboard with some slick moves.
The ageless wonder is still proving to the world he can probably play until he's 45. Nash's age curve is different than that of most players on the list.
When he arrived in Phoenix as a free agent in 2004 at the age of 30, it was thought that Nash's best days were behind him. Boy, did he prove everyone wrong. Nash went on to become a two-time MVP and led his Suns to three appearances in the Western Conference finals.
Now, at the age of 38, Nash is still producing at a high level. Although he is not as fast as he was in his Suns days running the seven-seconds-or-less offense, he is still just as smart and is arguably the second-most important player on the Lakers right now.
Dirk is in an interesting situation. Since returning from his knee injury, Dirk has had only one good game this season so far (against the defending champs, no less), but it does look like he is getting back on track.
His averages this season of 10.0 ppg and 4.3 rpg on 41 percent shooting are well below is career averages.
It's highly unlikely the Mavericks can contend for a championship even if Dirk returns, but the fact that remains is that Dirk is the best player on the Mavericks, and the team cannot compete in the playoffs without him.
Crawford has been consistent throughout his career. This season, he looks as good as when he was a member of the Bulls or Knicks, and maybe even better.
He was on a tear in the beginning of the season, posting over 20 points per game and close to 50 percent shooting from the field. He would probably be much higher on this list if he kept up his production, but it seems like he has come back down to earth as the high-volume, low-percentage scorer we've come to know him as.
Nonetheless, Crawford is having one of his better seasons at the age of 32. The explosive scorer has posted 50 or more points with three different teams in his career so far and can go off at any time. Even Kobe has been impressed, somewhat.
Even though his team may not be doing very well, Garnett is still playing at a high level. His numbers across the board look well below his career averages, but don't let that fool you.
When Garnett is on the floor, opposing teams score an average of 14.4 points less per 100 possessions. He had the highest net rating of all the Celtics last season with a plus-8.0, higher than both Rondo (plus-6.8) and Pierce (plus-6.1). He is also posting a rebounding percentage of 14.6, which is close to the total he posted in the 2009-2010 season when he went to the NBA Finals.
Love him or hate him, Garnett is still one of the best defenders and all-around players in the league, even at the age of 36. He can still ball, and that's why the Celtics signed him to play for three more years.
David West is having his best season since leaving New Orleans two years ago. Last season, West had a down year, mustering up just 12.8 ppg and 6.6 rpg in 29 minutes per game.
It's common thinking to believe that West had already started his decline a season ago, except that this year he has performed well above expectations. The skilled power forward is averaging 17.9 ppg and 7.9 rpg and is posting the fourth-best PER of his career.
He may be older, but West is the undeniable leader of the Pacers, and his play has been a major reason why his team is first in the Central Division.
When Paul Pierce retires, he will most likely go down as one of the top five Celtics of all time, and that's no pushover considering the team's long, successful history. He doesn't look any different this season than in any of his previous seasons.
He's 35 years old and has been playing the same way since he was 28. Earlier in his career, he was always in the backseat to superstars Kobe Bryant, Vince Carter and Tracy McGrady. But right now, only one of them has aged as well as Pierce.
He was never a flashy finisher around the rim or had supreme athleticism like Carter and McGrady. Instead, he utilizes the things given to him. He positions his strong body for post-ups and uses his craftiness to score points, and that has made him one of the more successful 35-year-olds in NBA history.
Just as we all thought Timmy was ready to slowly walk into the shadows to end his Hall of Fame career, he bounces back and is putting up All-Star numbers once again.
Duncan is putting up 17.8 ppg and 9.7 rpg in his 16th season in the NBA, and he remains the same defensive powerhouse he was back in his MVP years.
It seemed like after the Spurs got tossed out of the first round of the 2011 playoffs that Duncan had started his decline. But two seasons later, the Spurs are still among the top teams in the league, and Duncan is playing as great as ever. He will still be in the league for three more years, so we should enjoy the play of the greatest power forward in NBA history while it lasts.
Did you expect anyone else to be No. 1 on this list? The Black Mamba is having a career season, at age 34 no less. His Lakers aren't doing as well as everyone had expected, but Bryant has been playing like it's 2006, maybe even better.
Through 31 games this season, Bryant is recording a career high in true shooting percentage and effective field-goal percentage. His PER is also the second highest it's been for his whole career. Unbelievable.
After coming off of his previous season, which was arguably the worst since the 2004-2005 season, Bryant was expected to start a steady decline until his retirement, like a normal human being.
Except he isn't normal. He is arguably the greatest player of our generation, and I won't be surprised if he continues this high level of production until his retirement.